I'm mostly using the built-in Circles, which I find quite adequate for most purposes. I can share private things with Friends, be less selective about what I share with Friends & Acquaintances, and post things that I think could be widely useful or interesting as Public. I find that terribly useful.

I do have a couple of "topic" oriented Circles. For example, I have one for "Geeks" for sharing posts on videogames and comic books. While you are right that it's possible some of those posts might be of interest to others without me realizing it, limiting most of my posts to that circle ensures I don't spam friends who really don't give a damn. And it doesn't prevent me from occasionally sharing a post on a videogame with a wider audience.

It doesn't matter if most social sorting isn't clear cut on Google+. You can stil post to "your circles" and it becomes like Facebook.

The best part about Google+ to me is that it goes away with awkward things about Facebook and Skype.

1. I don't have to reject anyone's "friendship". I simply put them in a circle that I will not share with. This is different from putting people on "limited" because people know when they're limited.

2. The Hangouts feature takes away the awkward one-on-one video conversations when you don't really have anything to talk about. You start a hangout, more people join in, and conversation is bound to arise, even if it means making fun of each other's hair.

I think if anything the appeal of Google+ is the ability to manage your relationships better, and often ensure information you share is better suited to your chosen circles. Refining communication within Google+ doesn't have to be a bad thing, the question is how many people turning to Google+ stay there. Some more thoughts from my recent blog post: http://digitalspill.blog.co.uk/

One thing that people seem to overlook is the usefulness of being able to make circles overlap. We can't yet copy all of our 'friends' into 'acquaintances' but we can have 'friends' who are also 'rugby mates' who are also 'alumni'. This compensates for the nuances of whether someone is a 'friend' or a 'close friend', for example.

Is it not conceivable that circles will actually encourage more sharing? On Facebook (where assigning groups is a more convoluted process) I rarely share links with everyone because I realise different friends have different tastes, and not all of my tastes will be appreciated by all of my friends.

By making the process of focused sharing so easy, it's incredibly liberating on the side of the sharer. Admittedly it takes some control from the 'sharee', but that can be made up for with the sparks feature and a non-mutual following of someone whose feed matches your interests.

I agree. The 'circles' and 'follow anyone' features could work against each other in the (online) social space. They provide users with a lot of options - but too many options can sometimes be detrimental to the user experience.

I use the "friends" circle for only people who I would want to "hangout" with. I don't want to get stuck in the situation where someone I don't know really well wants to speak to me, or interupt a good conversation. Also, I am pleased that I can be more private with my posts, and not let my "aquaintances" or family know everything about me.

I mostly use circles as an inbound sort rather than an outbound filter. Granted this may broadcast to some people things which they aren't interested in. That could be remedied by hashtags. Until then they can mute the post.
Circles containing circles would be lovely. So would the ability to edit the circles a post list limited to.